1. Field of the Invention
The invention is directed to the field of closure mechanisms for hand tools and the like and principally to an improved full stroke compelling mechanism.
2. Description of the Prior Art
Various forms of mechanisms for hand tools and the like which require the user to complete the jaw closing stroke of the tool before the handles may be moved in a reverse direction are well known in the prior art. Examples of such mechanisms are disclosed in U.S. Pat. No. 2,696,747 issued Dec. 14, 1954 to M. D. Bergan; U.S. Pat. No. 2,784,621 issued Mar. 12, 1957 to M. L. Klinger; U.S. Pat. No. 3,262,342 issued July 26, 1966 to G. J. Filia; and U.S. Pat. No. 3,406,558 issued Oct. 22, 1968 to H. P. G. Tillmann et al. Each of these mechanisms comprise essentially a pawl and ratchet arrangement wherein the pawl is selectively inclined in one of two positions according to the direction of travel of the handle portions of the tool, the reversal of inclination of the pawl means being accomplished by release means located at either end of the ratchet means of the mechanism. In each case, however, the pawl and ratchet combination operates as a restriction on the reversal of movement of the handle portion in both directions of movement, that is, in both the closing and opening stroke of the tool so that once full closure is accomplished the handles must be brought to their fully opened position before the closing stroke may be reinstituted. An arrangement designed to at least partially overcome the above limitation is disclosed in U.S. Pat. No. 3,039,337 issued June 19, 1962 to R. G. Stuart-Prince. This device is shown to include a spring biased ratchet which is movable out of engagement with the opening portion of the tool stroke to permit the closure stroke to be reinstituted prior to completion of the opening stroke. The disclosed mechanism, however, involves an expensive and complex arrangement of parts composed of interfitting and sliding mechanisms which may be easily damaged in handling and use.